﻿//==================================================================
// Copyright (C) 2015 福流网络
// 作 者：江怀玉
// 日 期：2015-04-22
// 描 述：字符串加解密
// 版 本：1.00
// 修改历史纪录
// 版 本  修改时间      修改人            修改内容
//==================================================================

using System;
using System.Security.Cryptography;
using System.IO;
using System.Text;

namespace FL.Common
{
    /// <summary>
    /// 字符串加解密
    /// </summary>
    public class StringEncryptHelper
    {
        //默認密鑰向量
        //private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
        private static byte[] Keys = { 0x19, 0x31, 0x95, 0x06, 0x01, 0xAB, 0xCD, 0xEF };

        //加解密鑰
        const string encryptKey = "a$1SK&8?";

        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <returns>加密成功返回加密後的字符串，失敗返回原串</returns>
        public static string EncryptDES(string encryptString)
        {
            try
            {
                //byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <returns>解密成功返回解密後的字符串,失敗返回源串</returns>
        public static string DecryptDES(string decryptString)
        {
            try
            {
                //byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }
    }


}
